Thermal electric-circuit controller



Feb. 23 ,1926. 1,574,508

A G. w. OKEEFFE THERMAL ELECTRIC CIRCUIT CONTROLLER Filed April 28, 1922 ffl i 1529,12,

j@ ff M www Patented Feb. 23, i926.A

UNITED STATES GEORGE W. OKEEFFELOF DORCIIESTER, MASSACHUSETTS, ASSIGNOR, BY MESNE AS- SIGNMENTS, TO .CONDIT ELECTRICAL MANUFACTURING CORPORATION, OF BOS- TON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

THERMAL ELECTRIC-CIRCUIT CONTROLLER.

application led April 28, 1922. Serial No;`557,054.

To NZZ whom t may concern:

Be it knownv that I, GEORGE W. OKEEFFE, a citizen of the United States, residing at Dorchesteigin the county ot Suffolk and State ofMassacliusetts, have invented an Improvement in Thermal Electric-Circuit Controllers, ot which the following is a speciiication.

This invention relates to thermally-con-l ll trolled electric circuit controllers. An object of this invention is the provision of a circuit controller adapted to be received in and supported by spring clips similar to a cartridge type electric lfuse.

A further object is to provide a thermal circuit controller with an electrical heating element for the thermal clement; and with means for applying heating elements of various capacities to the controller whereby 2" the controller may be adjustedvto operate at various different values of current passed through the heating element.

A further object is to provide a thermal circuit controller with means by which the contact members may be inspected and adjusted externally of the enclosing casing and after'the component parts thereof have been assembled within the casing..

A further object is generally to improve the construction and operation of thermally controlled circuit controllers. A

Certain features of this invention are d isclosed in my co-pending application Serial No. 557,055, filed concurrently herewith.

Fig. 1 is a plan view of a thermal circuit' controller embodying the invention.

Fig. 2' is an axial sectional elevation of the tontrollersupported in spring clips.

Fig. 3 is a left-hand end view of the controller of Fig. 1.l Fig. 4 is a sectionv along .line 4-4 .of Fig. 2. Fig. 5 is a section similar to Fig. 4 but with the thermal element and stationary contact member arranged Ato control a normally open control circuit.

Fig. 6 is a right-hand end view of the controller of Fig. 1.

Fig. 7 is a sec-tion through an end cap illustrating the attached tubular thermal element. i

Fig. 8 is a view of the insulating plug bearing the stationary contact member..

Fig. 9 is an elevation, partly in section of the controller having a heating element adapted for low values of current.

Fig. 10 is a section of the controller of Fig. 1 without the heating element.

Fig. 11 is a diagram of a typical control lcircuit including the circuit controller.

Fig. 12 is a transverse cross-section, enlarged, through a convolution of the thermal element. y

lAs here shown, the thermal circuit con troller embodying the invention is tubular in form and is adapted to be received in and supported by the spring clips 10 and 11 in a manner similar to a cartridge type enclosed electric fuse. `Said controller includes the tubular enclosing casing l 13 of insulating material having the metal caps 14 and 15 disposed on and sealing the ends of said casing. In assembled condition, said end caps are preferably secured permanently in place by suitable means, as crimping them over the casing. The thermal element comprises the tubular and spiral coil 16 preferably iormed of thermostatic metal and adapted to expand and rotate about its axis when heated. The tliermostatic metal forming the thermal element 16 may comprise two metals having dissimilar coeiiicients of expansion united mechanically in any suitable manner to forni, in effect, a single sheet or strip of material having marked suscepti# bility to temperature variations. Fig. 12 illustrates in cross-section such a strip of thermostatic metal wherein the dissimilar metals composing said strip are represented by m and y. One end of said coil may be secured permanently to one of the end caps, as the end cap 14 by suitable means, and the speciic securing means here shown comprises a tube 17 which is inserted in the end of and is secured to the spiral coil by solder. Said tube has a reduced portion 18 which is extended through an aperture 19 in the end cap 14 and the extended end "of the reduced portion 18 may be expanded over the end face of the end cap to secure the tiibe and spiral coil securely in place. The aperture 19 .in said end cap is disposed below the center of the cap whereby the spiral coil is l0- cated below the axis of the enclosing casin Said end cap 14 may also be formed wit other apertures 20 in its end wall adapted to 105 serve as vents for the controller.

Thefree end portion 21 of the thermal ltain said plug in position. Before the'end vcap 15 is secured finally to the casing, said plug' may be moved angularly in the casing whereby to align the elements carried by it with the components of the controller but will be held in adjusted position by said end cap when it is fixed permanently to the casin Said plug 23 is formed with the eccentrically disposed projecting member 25,-here shown of segmental shape, which protrudes through a correspondingly shaped aperture in the end lWall of the end cap 15 and extends beyond the end cap to form an insulating member for the terminal or fixed contact member of the controller to which a lead of the control circuit is adapted to be eonnected.

'-Saidcontact member comprises the bar 26. which; is enclosed Within said insulating pluV4 23. .The outer end 26L of said bar exten s outwardlybeyond the projecting member 25 ofthe plug and may be provided with attaching means, as the screw 27, for a lead `of the control circuit.

The inner end 26" of'sad bar is extended beyond the inner end of said plug within the enclosing casing 13 and bears the contact which may comprise the screw 28 adjustably threaded in said inner end 26b and adapted to/bepeiigaged by oneor the other of the contact points 22 car-v ried by the thermal element 16. In Fig. 4, the thermal element and fixed contact member are arranged to lcontrol av normally closed control circuit and, when said thermal element is heated, it expands and rotates about its axis toward .the left to interrupt the control circuit.

Iii Fig. 5, the fixed contact member and thermall element are arranged tocontrol .a

`normally open control circuit and, when heated, the thermal element rotates toward which is extended through it and the cylindrical projection 30 thereof and ali gued 'with the passa e 32 in the tube 17 by which the thermal e ement is secured to and electrically l connected With-the end cap 14, and an aperture in the end, cap 15.4

The heating element may comprise an electrically conducting rod 35 which is extendedthrough the tubular thermal element and the aligned passages. After the" other elements of the controller have been assembled, said rod may be fixed permanently in position and in electrical connection with the end caps by suitable means as solder applied over the ends of said rod in the end caps.

"When current above apredetermined value passes through the power circuit 40, Fig. 11, in which the controller with its heating element 35'is included, the heating element becomes heated and givesup 'its'f heat to -the thermal element' 16 and causes said element to'expand and make or break contact with the fixed contact member 26, as the case may be, and control the control circuit 41 to operate the switch 42 or other protective device.

rIihe current value at which the controller is set to operate is designed to be varied by varying the character of the heating element. When the controller is adapted to operate at relatively large values of current, the heating element may be a rod hav.

ing relativelylow electrical' resistance, as, for instance, a copper rod. For lesser values of current the rod may be of material hav? ing higher resistance as, for instance, Monel metal. For relatively low values of current, the heating element may be a carbon rod.

Fig. 9 illustrates the controller having a carbon rod 45 as the heating element. Said rod may have the metal plated end portions 46 by which it may be soldered to the end caps and electrically connected therewith.

The controller is .adapted to be manufactured as a unit Without the heating element,

as illustrated in Fig. 10, and heating elements having various heating capacities are adapted to be inserted and permanently secured in the controller to provide a controller adapted to operate at various predetermined values of current.

In assembling the component parts of the controller, it is desirable to inspect the relative position of the movable and fixed contact points and, if necessary, to adjust them into proper relative positions, before the end caps are fxejd permanently to the enclosing casing. For this purpose, the enclosing casing 13 is formed with the eep hole 60 disposed above .the contact points, and the adjusting holes 61 and 62 on opposite sides of the peep hole. The contact oints are visible through the peep hole an the fixed contact point 28 may be adjusted by the inserwith a normal heating effect on the thermal element as governed, by the heat radiation from the controller, as through `the vent holes 20, from the exposed surface ofthe controller components, as the end cap 14, etc. The operation of the controller for some moderate value of current different than that provided by a particular heating element may be obtained by Varying the position of the adustable contact point 28 with respect to the thermalelement whereby to require a greater or-less deiection of the thermal element before making or breaking contact, as the case may be, with the :adj ustable contact point. The temperature of the thermal' element at which it will operate to control the control circuitv will thereby be varied somewhatfrom its normal operating temperature, but this, ordinarily7 is of no particular importance. u

It is .to noted that the lower vent holes 20 in-the end cap 14, see Fig. 3, are disposed adj acent the thermal element whereby to direct cool air over the thermal element and cool it whereby' to provide for the operation of said element at increased values of current passed through the heating element; and also to provide for the more rapid resetting of thel thermal element. For operation -on currents of relatively low values, the Vent holes may be reduced in size, or eliminated entirely.

It is also to be noted thattheheating elelment is covered and heat-insulated for a portion of the length by the insulating plug 23 and the projection 30 thereof.A With this arrangement, the heat-insulated portion of the heating elementv becomes heated to a higher degree than the unshielded portion thereof and transmits its heat by conduction K It is to be noted that the electrical heatino" unit is in electrical and therefore inA therma connection with the end caps 14 and 15 and, consequently, under certain conditions, said end caps act as heat radiators for the heatconductivity is low and consequently little heat will be conducted into and radiated from the endcaps. With heating units of low resistance, and high current carrying capacity, the thermal resistance is low and consequently the amount of heat conducted along the heating unit and into and dissipated by the end capsv may be of some substantial amount. With this'arrangement, the upper operating range of the controller may be substantially extended without increasing the diameter, or other dimensions, of the heating unit.

The invention may be otherwise modified without departing` from the spirit thereof. I'claim: 1. A thermal electric circuit controller including a tubular insulating enclosing casing, metal caps on the ends thereof, a fixed contact member disposed within the easing, a thermally` expansible element .connected electrically with one of said end caps and arranged within said casing in operative relation with said fixed Contact member,

and a cylindrically-formed electric heating element disposed'within .said casing tov lie along the length of and close to said thermally expansible element and having its'ends electrically connected with said metal caps.

2.. A thermal electric circuit controller including an enclosing casing, metal end caps carried thereby, an insulated stationary contact member carried by said casing and .having attaching means for a circuit lead at the outer end thereof, `and extended through one of said end caps, and insulated from said end cap, a thermally expansible element disposed within said Casin and heating means for said expansible e ement disposed within said casing, and electrically connected with said end` caps.

3. A thermal electric circuit controller including an enclosing casing, end caps carried thereby, a fixed contact member carried by said casing, a thermal element disposed within said' casing in operative relatie-n with said contact member, andan electrical heating elementl comprising la resistance rod extended within said casing in heat-imparting relation with said thermal element and electrically connecting said end caps.`

4. A thermal electric circuit controller including an enclosing casing, end caps carriedthereby, an insulated fixed contact member carried by 4and extended through said casing, a thermal element having tubular formation disposed within said casing in operativerelation with said fixed contact member and an electrical heating element disposedwithin said tubular thermal element.`

5. A thermal electric circuit controller including a fixed contact member, a spiral thermal element having its convolutions arranged in tubular formation and cooperating With saidv contact member, and an electrical heating element disposed Within and in heat-imparting relation with said thermal element.

6. A thermal electric circuit controller including a xed contact member, a spiral thermall element having tubular formation with its convolutions arranged side by side, said element lixed at one end and having its free end disposed in cooperative relation with said contact member, and an electrical 4heating element disposed within said thermal element` and in heat-imparting relation therewith.

7. A thermal electric circuit controller including a fixed contact 'memben a spiral thermal element having tubular formation with its convolutions arranged side by side, said element ixedly supported at one end and having its free end disposed to engage and disengage said fixed contact member, and an electrical heating element comprising a resistance rod disposed Within said spiral thermal element and in heat-imparting relation therewith. l 8. A thermal electric circuit controller including an enclosing casing, end caps carried thereby, an. insulated contact member carried b v and extended beyond said casing, a spiral thermal element carried by one of said end caps, and an electrical heating elemen-t disposed within .said thermal element and `electrically connected With said yend ca s.

g. A thermal electric circuit controller including an enclosing casing, end vcaps carried thereby, an insulated fixed contact member carried by and extended Within one end of said casing on one side of the axis thereof, a thermal element extended Within the other end of said casing on the opposite side of the axis thereof and having an end portion extended into cooperative relation with said fixed contact member, and an electrical heating 'element disposed. Within said casing in heat-imparting relation with said thermal element.

10. A thermal electric circuit controller including an enclosing casing, end caps carried thereby, an insulated fixed contact member carried by said casing on one side of the axis thereof, a thermal element fixed to one of said en'd caps and .disposed Within said casing on the opposite side of the axis thereof having an end portion extended into cooperative relation withsaid fixed Contact member. and an electrical heating element disposed Within said casing in heat-imparting relation with said thermal element and electrically connected with and supported by said end caps.

11. A thermal electric circuit controller including a. tubular enclosing casing, end caps carried thereby, an insulated fixed contact member carried by said casing, a thermal element disposed Within saidcasing in cooperative relation With said lixe'd contact member, said end ca s having aligned apertures therein adapted) to receive and sup ort an electrical heating element for said t ermal element. 4

l2. A thermal electric circuit controller including atubular enclosing casing, end caps carried thereby, an insulated ixed contact member carried by said casing, a thermal element disposed Within said casing in cooperative relation with said fixed contact member, said end caps having aligned apertures therein adapted to receive and support an electrical heating element for said thermal element and a rigid electrical heating element extended Within said casing and received in and supported by the aligned apertures in said end caps.

13. A thermal electric circuit controller Including a tubular enclosing casing, end caps carried thereby, an insulating. plug received in one end of said casing, a fixed contact member carried by said plug and extended Within said casing, a thermal element 'disposed Within vsaid casing in coo erative relation with said fixed contact mem er, and an electrical heating element for said thermal element disposed Within said casing and electrically connecting said end caps.

11i. A thermal electric circuit controller including a tubular enclosing casing, end caps carried thereby, an insulating plug received Within one end of said casing, a contact membercarried by said plug and extended Within said casing, a thermal element having tubular formation carried by one of said end caps having its free end disposed in cooperative relation with said Contact member, and an electrical heating unit extended through said tubular thermal element and between` and electrically connected with said end caps.

15. A thermal electric circuit controller including a s iral thermal element fixed at one end and aving its other end extended laterally outward beyond the bounds of the spiral and free for angular movement, a fixed contact member cooperating with the free end of said thermal element, and fixed supporting means on which the free end of said thermal element `is angularly movable.

16.. A thermal electric circuit controller including a spiral thermal element xed at one end and having its other end free for angular movement, a fixed contact member cooperating with the free end of said thermal element, supporting means on which the free end of said thermal element is angularly movable, and an electrical heating unit comprising a rod extending through said incisos means. .A l.

17. A thermal electric circuit controller 1ncluding a tubular enclosing casing of insulating material, end caps carried thereby, a spiral `thermal element having ne end fixed to and connected electrically with one of said end caps and extended Within one end of said casing and having its inner end free to move angularly, an insulating plug received within the other 'end of said casing, a fixed contact member carried by said plug and disposed in cooperative relation with the movable end of said thermal element,said insulating plug having a supporting projection for said tubular thermal element received loosely Within the in ner end of said thermal element. l

18.` A thermal electric circuit controller including a tubular enclosing casing of insulatingpmaterial, end caps carried thereby, a spira t thermal element having one end fixed to and connected electrically with one of said end caps and extended within one end of said casing and having its inner end free to move angularly, an insulating plug receiv ed within the other end of said casing, a lixed contact member carriedby said plug and disposed in cooperative relation with the movable end of said thermal element, said insulating plug having a supporting projection for said thermal element received v loosely Within the inner end of said thermal elementsaid endcaps a'nd insulating plug..

having aligned apertures arranged to receive an electrical heating unit.

19. A- thermal electric circuitcontroller including a tubular enclosing casing of insulating material, end caps carried thereby, a spiral thermal element havingone end fixed to and connected electrically with one or said end caps and extended Within one end of said casing and having its inner end free to move angularly, an insulating plug received Within the other endof said casing, a ixed contact member carried by ,said

plug and disposed in cooperative relation with the movable end of said thermal element, said insulating plug having a supporting/projection for said thermal element received loosely within the inner end of said thermal element said end caps and insulating plug having aligned apertures arranged to receive an electrical heating unit and an electrical heating unit comprising a resistt ance rod received in said aligned apertures caps carried by the ends Iof said casing, an

insulated contact member comprising a bar disposed Within .said casing having a terininal extended outwardly beyond the end of the casing, and a thermally expansible element disposed within said casing in operative relation with the inner end of said bar. A

2l. A thermal electric circuit controller including a tubular enclosing casing, end caps carried by the ends of said casing, an insulating member received in4 one end of said casing and extended outwardly beyond the end thereof, and the end cap on the casing, a contact member carried by said insulating member having its inner end disposed Within the casing and its (inter end extended outwardly through the end of said insulating member, and a thermally expansible member disposed Within said casing in opera-tive relation with said contact member.

22. A thermal electric circuit controller including a tubular enclosing casing, end

lcaps carried thereby, stationary and movable contact members disposedwithin said casing, a thermal element controlling one of said contact members, said casing having a peep hole through its side Wall disposed above said contact members.

A thermal electric circuit controller including a tubular enclosing casing, end caps carried thereby, stationary and movable contact members disposed Within said casing, a thermal element controlling one of Said contact members, said casing having a peep hole through its side wall disposed above said contact member and an adjusting hole through its side Walltfor said stationary contact member. n

.94. A thermal electric circuit controller including a tubular enclosing casing, end caps carried thereby, a thermally expansible ele ment disposed Within said casing, a xed contact member disposed Within said casing in cooperative relation with said thermal element, said casing having a peep hole through its side Wall disposed above said fixed contact member and thermal element.

25. A thermal electric circuit controller `including a tubular enclosing casing, stationary and movable contact members disposed Within saidy casing, a thermal element controlling one of said Contact members, said casing having a peep hole through vits side wall above said contact members, and sealing means for said peep hole.

26. A thermal, electric circuit controller including a tubular enclosing casing, conductingend caps on the ends thereof, an insulating plug received Within one end of said casing and having a projection extended ing`a terminal-portion thereof extended outsaid lixed contact member, and means to\ heat said thermally expansible element.

2T. A thermal electric circuit controller having` a thermally expan'sible element, a fixed contact member cooperating therewith, an electrical heating element for said expansible element having a portion thereof exposed `for transfer of heat to said expansible element and having another portion thereof shielded from heat-radiation.

28. A thermal electric circuit'controller comprising a thermally expansible element, a cooperating contact member, an electric heating element for said thermally expanelectrical heating element for the thermally expansible element, and a heat radiator arranged in thermal connctionwith at least arranged in -thermal connection with said,-

one end of said heating element.

including the combination of an enclosing casing, a thermallydexpansible elem'entdis-y posed therein, an electrical heating element l' for the thermally expansible element disposed within said casing, and heat radiators heating element and disposed without said casing.

posed within said casing having exposed end-terminals, and a spiral thermal element disposed within said casing'and enclosing said heating element.

32. The combination of a tubular enclosing casing, an electrical heating element disposed within said casing having exposed end-terminals, a spiral thermal element disposed within said casing and enclosing said heating element having oneend fixed and the other end free to move under influence I of heat.

33. The combination of a tubular enclosing casing, end caps thereon, an electricall 30. A thermal electric circuit controller nav-1,508

ment and having a good thermal connection with at least one of said end caps.

34:. The combination" of a tubular enclosing casing, end terminals thereon, an electrical heating element extended Within said casing and connected with said end terminals, and a spiral thermal element enclosing 1 36. 'Iihe combination of a tubular enclosing.cas1ng,`an electrical heating element dis- .posed within said casing having exposed end-terminals, anda thermal element disposed Within said casing in heat receiving 'relation with said vheating I element, said thermal element having one end fixed and thefother end free to move, and said casing having an aperture adjacent the free end of said thermal element and across which aperture the vfree end of said thermal element is ling casing, a metal end cap forming a closure'fnifv one end ofsaid casing, an electric c heating element disposed within said casing 31. The combination of a tubula-r enclos-- ing casing, an electrical heating element disone end of said casing, a; conducting support carried-'by said end cap within'said casing, an electric heating element disposed within said casing and connected electrically with said support and also thermally therewith for material heat flow therebetween, and a thermally expansible member disposed within said casing in proximity with said heating element and connected electritallv with said support and also thermally therewith for material heat How therebetween.

In testimony whereof I have signed my name to this specification.A

GEORGE W. OKEEFFFI. 

